1. Field of the Invention
The present invention relates to a capsule endoscope which picks up an image of the body cavity by introducing, in the living body, a capsule portion incorporating an observation optical unit and an illuminating unit.
2. Description of the Related Art
Recently, an endoscope apparatus has recently been used. In the endoscope apparatus, an observing unit arranged to an edge portion of an elongated inserting portion of an endoscope is inserted to an observed portion in the body cavity as a target. The observing unit faces the observed portion as the target and thus an observed image of the observed portion as the target is displayed on a screen of an observing device.
The endoscope in the endoscope apparatus comprises an observing unit which captures an image of a subject in the body cavity and an observing device which displays an observed image, which are connected by an elongated inserting portion. Therefore, the inserting portion needs to be inserted near the observed portion as the target so that the observing unit faces the observed portion as the target and the observed image is obtained. However, the inserting portion must be smoothly introduced near the observed portion as the target with skilled art.
In recent years, a capsule endoscope apparatus integrally having a capsule endoscope and an observing device has been proposed. The capsule endoscope integrally includes an observation optical unit, an illuminating unit, and a receiving and transmitting device in a capsule portion.
Therefore, the capsule portion is swallowed like a tablet and then the observed image of the subject captured by the observing unit is transmitted to the observing device as an external device via the receiving and transmitting device. Thus, the observed image of the subject captured by the observing unit in the capsule portion is displayed on a screen of the observing device.
For example, Japanese Unexamined Patent Application Publication No. 2001-91860 discloses a capsule endoscope. The capsule endoscope includes an objective lens in an inner space formed by approximately semi-spherical transparent cover and a light emitting diode arranged to sandwich the objective lens. In the capsule endoscope, a subject is illuminated by the light emitting diode, an image of the subject is formed on an image sensor by an objective optical system, and the observed image is obtained.